The decision by a Missouri judge on Monday to go easy on Cornealious “Mike” Anderson after a bureaucratic snafu meant he never served a 13-year prison sentence for robbing a Burger King has been widely hailed as an act of perfect mercy, even by prosecutors and Mr. Anderson’s victim.

Mississippi County Associate Circuit Judge Terry Lynn Brown told Anderson “to go home” after a 10-minute hearing, noting, “You've been a good father. You've been a good husband. You've been a good taxpaying citizen of the state of Missouri. That leads me to believe that you are a good man and a changed man."

The judge’s handling of the Anderson case is “quirky” and a one-off given the unique circumstances, says Marc Miller, the dean of the University of Arizona College of Law. Yet it comes amid a growing backlash to tough sentencing laws. For example, Americans now prefer rehabilitation to jail time for nonviolent drug offenders, a shift from a decade ago, according to a Pew poll.

In that context, Anderson's story and Judge Brown's decision offer at least a glimpse at the possibilities for rehabilitation and redemption.

“We have a system sanction and punishment that has become excessive by historical and global standards,” says Professor Miller. “And when you see the potential of people [like Anderson] who have made terrible errors and caused harm and nonetheless succeed as a member of society, it makes you wonder how many other people can do that, and whether harsh sanctions remove opportunities for mercy and redemption.”

The case of Anderson became a cause célèbre as thousands rooted for his release via a petition on Change.org. Anderson had been sentenced to 13 years for robbing an assistant manager at a Burger King. But the prison order never came, and he instead went on to marry, divorce, marry again, raise four children, start a construction business, and abide by all laws save a few traffic violations. Earlier this year, the state prison system realized its mistake when it went to release Anderson. He was immediately taken to jail.

Even in cases where mercy seems appropriate, American judges struggle with political optics. A sweeping new national study of sentencing shows regional, gender, and political disparities in sentencing, with Southern judges, for example, being the harshest, and judges in the West being more lenient.

The push and pull between judicial independence and mandatory sentencing goes back decades in the US. As far back as 1960, Judge Irving Kaufman wrote in The Atlantic that “no other act of [a judge] carries greater potentialities for good or evil than the determination of how society will treat its transgressors." The most significant recent development came in 2005, when the Supreme Court struck down mandatory minimum sentencing, allowing legislative guidelines to be used as suggestions, not mandates, to judges.

To critics, that decision allows judges too much leeway, sometimes with disastrous consequences.

"A criminal committing a federal crime should receive similar punishment regardless of whether the crime was committed in Richmond, Va., or Richmond, Calif., and that's why I am deeply concerned about what's happening to federal sentencing," Sen. Jim Sensenbrenner (R) of Wisconsin said in urging Congress to revisit sentencing laws in 2012.

In the meantime, many states, including Texas, have passed laws that shorten sentences for some crimes, and Congress is looking at legislation called the Smarter Sentencing Act that would do much the same. Most poignantly, Attorney General Eric Holder recently told Americans that President Obama has vowed to use his pardon powers to release potentially thousands of people in prison for nonviolent drug violations.

Last month, the US Sentencing Commission, which creates federal guidelines, voted to ease up on various drug offenses, a major move that could reduce about 70 percent of all drug trafficking sentences by 11 months.

“It’s not like they’re getting a break, but they’re getting something of a more reasonable sentence,” Federal Public Defender Donna Elm told the Tampa Bay Times. “They’re still getting substantial punishment, but it is going to reduce just warehousing people in prison long beyond the deterrent effects.”

It is of course unclear where a 13-year prison sentence would have steered Anderson. But it was clear the judge had no more business with the master carpenter, mandating that he did not have to check in with a parole officer.